Initiation l’echangisme (1980) (Jean-Claude Roy, Alpha France)

France Lomay’s husband (Jacques Gatteau) is a salesman of sexy undies who calls on Dominique Saint Clair. She invites him to watch her and her husband (Dominique Aveline) have sex and then to join in.
On a later occasion he goes with her and her husband to a swingers’ club along with Karine Gambier. The receptionist is a brunette, presumably Deborah. Another couple are already present – the woman has dark curly hair (Sophie Duflot).
Later Jacques visits Karine and the receptionist arrives and he watches a g/g session.
Eventually he persuades his wife to come to the club and, once there, though reluctant at first, she is persuaded to join in the antics. Mika Barthel is present in this scene as well as Karine, Dominique Saint Claire and the receptionist, but not Sophie Duflot. Gabriel Pontello is also in this scene.